Electric switch



May 3, 1949. A. PALME ETAL ELECTRIC SWITCH Filed Dec. 4, 1945 O 5 I a m I. o n I l 7 8 9 m a Q O M GO A mm x I W UL m m LW n/n/h A/ W// W 6 INSULATION.

Inventors:

efiwfw m: m6 0 c t P .t u A n r tn i Q? A T Patented May 3, 1949 ELEQJTRHC SWITQH Arthur Palme and Orin P. McCarty, littsileld, Mass, designers to General Electric ilorhpany, a corporation of New York Application li ccember l, 1945, Serial No. 5532,??5

ll (@l. Zllll 'lddl g Fur inventi n relates to electric switches and more "particularly to electric switches having seug moderate power currents such as transer magnetiuiug currents or the like, as well for carrying normal load clu'reuts and also ctioning to connect the circuit. llpeciflour inveni an improvement on eon utly filed copending Warnoclr application, assigned to the same assignee icatlon. aitches for interrupting the 'nccluine; current of power transformers inlay nmersed in liquid insulating dielectric such r a halo Jted in drocarlooh. when arcs we. in all there is always the hazard of fire. or hand, when arcs are drawn able dielectric, there is always son'ce decomposition of the halororocarbons and the consequent formacorros ve decomposition products.

ll that when power transformers power source, a fairly high co .1 1. cirlllc 1s capable of interrupting etizing currents may not he oapahle of car. e transformer inrush currents for short eriod oi time. It would be desi able to provide a switch of the above mentioned typ which the interrupting contacts werenot ed to carry the transformer iurush curcuit interrupt transformer magic Accordingly, it is an object of invention to provide a new and improved sequential circuit controlling electric switch having circuit closing contacts are capable of carrying fairly high currents and are sequentially interrelated with hermetically sealed interrupting or arcing contacts that are capable of efilclently interrupting moderate load currents in high voltage power circuits in disconnecting such power circuits.

It is another object of our invention to provide a switch of the above described type capable of being immersed in any form of liquid insulating dielectric without danger of fire or deleterious effeet on the liquid dielectric when operating to interrupt moderate load currents.

Still another object of our invention is to provide a switch for interrupting the magnetizing current of power transformers which switch includes sequentially operable circuit closing contacts and interrupting contacts arranged so that the interrupting contacts are never subjected to transformer inrush currents.

Further objects and advantages of our invenque-utlal contacts which are capable interformer M tion will become apoaent as the following description proceeds andv the features of novelty which characterize our invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a hotter understanding of our invention reference may be had to the accompanying draw ring in which Fig is an elevatlonal View, partly in section, of a switch embodying our invention Referring now to the drawing. we have illustrated an electric switch generally indicated at i, which is shown as a transformer disconnectin switch. a portion of transformer is gel zen ally illustrated 1-3 and includes a housing which supports which elect ical connections rom. the transught to circuit terminal Switch is mounted within a container ll supported our transiorrner housing 3 and preferably Tooth th housing and the container are filled with liquid insulating dielectric which may comprise oil a halogenated hydrocarbon. It should be understood that, although we have disclosed our switch as arranged to be immersed in liquid insulating dielectric, it is equally capable of satisfactory operation when mounted in air the manner disclosed in the above mentioned copending Warnock application.

A second circuit terminal is illustrated in Fig. l as being supported on an insulating bushing ll fastened within container or housing d and electrical connections from terminal extend through bushing 3 to any suitable power circuit such as a power line or the like,

Circuit terminals 5 and l are arranged to be electrically interconnected by a pair of relatively movable main current carrying switch members illustrated as a stationary switch member or contact comprising contact bars 9 provided with contact clips i0, and a movable blade or contact H pivotally mounted as indicated at H, to suitable means within housing 8. The numeral in will hereinafter be used when referring generally to the stationary main current carrying contact. Movable blade ii is provided with a contact ring l3 which is engaged in sliding electrical engagement with contact fingers or brushes i4 supported from terminal '1.

For the purpose of interrupting moderate power currents when the electric switch of our invention is to be opened, there is provided a circuit interrupter generally indicated at I! insulating bushing through which is carried by one of the relatively movable switch members. As illustrated in the drawing, circuit interrupter I is associated with movable blade I! It should be understood, however, that circuit interrupter could be associated with the stationary contact It.

Circuit interrupter l5 comprises a hermetically sealed enclosure 16 formed of insulating material, such as glass or the like, which is essentially an evacuated envelope for housing a pair of relatively movable arcing or interrupting contacts I! and I8. Interrupting contact I! is illustrated as a stationary contact and is electrically connected to movable blade I I by means of a flexible conductor l9. Movable arcing contact 18, on the other hand, is mounted on a rod 20 which extends outside of housing l6 through a flexible thin-walled metallic diaphragm 2i. The portion of rod 20 extending outside of housing 16 is, in effect, a contact actuating member and is provided with the end portion 22 which will hereinafter be referred to as actuating member 22. As illustrated in the drawing, relatively movable arcing or interrupting contacts I! and 18 are preferably biased to the closed position by means of the flexible metallic diaphragm 2i and are opened by operation of actuating member 22 causing flexing of diaphragm 2|. Essentially the circuit interrupter i5 is a vacuum switch of the type disclosed in Jones Patent 2,383,973, granted September 4, 1945, and assigned to the same assignee as the present application.

Circuit interrupter I 5 is illustrated as being supported on a block of insulating material 23 by means of a band 24 partially encircling a portion of the housing thereof. Insulating material 23 is supported by suitable means on moving blade Ii.

Also supported on insulating block 23 is a double armed lever 25 comprising an auxiliary terminal 26 and a switch actuating arm 21. Double armed lever 25 is pivotally mounted to insulating block 23 as indicated at 28 in such a position that clockwise rotation as viewed in Fig. 2 will cause arm 21 to engage contact actuating member 22 with the resultant opening of arcing or interrupting contacts I! and (8. A suitable spring 29 tends to hold double armed lever 25 normally in the midposition shown in Fig. 2 with a small gap between arm 21 and contact actuating member 22, thereby permitting slight movement of double armed lever 25 without opening of the arcing contacts I1 and IS. The double armed lever 25, which is formed of conducting material and furnishes an auxiliary terminal 26, is electrically connected by means of a flexible electrical conductor 30 with rod 20 and consequently with movable arcing contact l8.

Associated with the stationary contact I0 adapted to engage movable blade II is a supporting member 3! formed of insulating material which extends for a considerable distance along the path of movable blade ll during the circuit opening operatiominsulating supporting member 3| is provided along a portion of its under surface with a conducting liner 32 electrically connected to one of the contact clips l0. Conducting liner 32 is, in efiect, an auxiliary contact surface in the form of a cam surface. At a distance X from the end of the cam surface or metal liner 32, not connected to stationary contact I0, is a downwardly extending surfaceor portion designated by the numeral 33 in Fig. 2. The auxiliary contact surface comprising the liner 32 during the circuit opening operation is adapted to be engaged by the auxiliary terminal 26. It is obvious that when this occurs the auxiliary contact surface 32, auxiliary terminal 26, flexible lead 33, rod 20, arcing contacts I1 and I8 and flexible lead l9 provide a shunt electrical connection across the relatively movable switch members It and II. An important feature of our invention is the arrangement of the current carrying contacts and the arcing contacts whereby the current carrying contacts are first opened, thereby shunting all of the power current through circuit interrupter ii. In the fully closed position of the switch shown by solid lines in Figs. 1 and 2, all of the current flows through the current carrying contacts and the shunt circuit is open by virtue of the fact that auxiliary contact surface 32 and auxiliary terminal 26 are electrically disengaged.

During the circuit opening operation contact blade ll rotates about pivot I2 in a counterclockwise direction, as viewed in Fig. 1. However, before disengagement between current carrying contacts occurs, auxiliary terminal 26 electrically engages cam surface 32 thereby completing the shunt circuit through interrupting contacts I! and I3. Continued opening movement of switch I causes the main current carrying contacts to be completely disengaged with the resultant transfer of all the current to the shunt circuit comprising arcing contacts l1 and I3. After the current carrying contacts have been completely disengaged and the current transferred to the shunt circuit, the auxiliary terminal 26 of double armed lever 25 engages the portion 33 of cam surface 32 causing lever 25 to rotate in a clockwise direction with the resultant engagement of arm 21 of actuating member 22 and the opening of interrupting contacts I! and IS. The arc drawn will be interrupted within the evacuated envelope in a very effective manner even though the voltage involved may behigh. Continued movement of blade H for the distance X in Fig. 2 maintains electric contact between auxiliary terminal 26 and cam surface 32 to give ample time for actual current rupture. Continued movement of blade H for the distance Y prevents the spring 29 from returning the double armed lever 25 to its intermediate position whereby a double gap in the shunt circuit is provided, one between arcing contacts I! and I8 and an additional gap between auxiliary terminal 26 and cam surface 32. When the switch reaches its fully open position shown in dotted lines in Fig. 1, double armed lever 25 has assumed its intermediate position and arcing contacts I! and 18 have reclosed.

Although the interrupting contacts l1 and I8 are very effective to interrupt high voltage arcs, there is a possibility that they might be damaged by the heavy inrush currents which flow when the transformer is connected to a power supply. It is an important feature of our invention that during the switch closing operation double armed lever 25 first engages insulating member 3| to rotate it in a counterclockwise direction so that it cannot engage cam surface 32 and complete the shunt circuit through arcing contacts I! and I8 until after the main current carrying contacts 10 and II have closed to take the inrush current. When the main current carrying contacts are fully closed, double armed lever 25 is free to move clockwise to its original position under the influence of spring 29 after the free end of the arm 26 rides off the inner end of the conducting liner 32 because the pivotal point 28 is low enough to permit such movement.

In view of the detailed description included above, the operation or our invention will be obvious to those sldlled in the art.

It will be understood that the insulating =evacuated envelope It prevents any are which is drawn from in any way deleteriously aflecting the surrounding medium whether it be air, oil or other insulating liquid dielectric. It is furthermore obvious that with our invention we have utilized the very favorable characteristic or vacuum switches of interrupting moderate currents at high voltages while not subjecting the vacuum switch to high transformer inrush currents.

While we have shown and described a particular embodiment of our invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from our invention in its broader aspects and we, therefore, aim in the appended claims to cover all such changes and modifications as ic'ail Within the true spirit and scope of our invention.

What we cit as new and desire to secure Letters the United States is:

l. a switch, a pair of relatively movable cooperating contact members including 9. etc. tionary Can't-Bit and a. niovable blade, an in sulating st art on said blade, a vacuum switch mounted. on said insulating support comprising a pair of interrupting contacts enclosed by an evacuated envelope having a flexible metallic diaphragm as portion thereof, an actuating member through said diaphragm for operating saidi corrupting contacts from outside envelope, conducting cam surface associated with stationary contact, a conducting member pLvote-f said insulating support electrically co acted to said blade through said arcing contacts so complete circuit in parallel with said contact members when said conductin member said cam surface, and means on cam surface icr causing move ment of said conducting member to open said i Eerrupting contacts and interrupt the current 1 .oich has been transferred from said contact members to interrupting contacts,

n a switch for interrupting transformer etizing currents of the type immersed in isulating liquid dielectric, a pair of relatively movable cooperating contact members, a pair 1' movable arcing contacts, an evacuenvciope for housing said arcing contacts including a flexible metallic diaphragm whereby relative movement of said arcing contacts may be obtained by actuation of the diaphragm exterioriy oi the envelope, means for normally biasing said arcing contacts to the closed position, said evacuated envelope being supported on one of said contact members but insulated therefrom, a pivotaliy mounted lever electrically connected to one of said contact members through said arcing contacts, and means electrically connected with said other contact member for electrically engaging said lever to contact said arcing contacts in shunt with said contact members following initial movement of said contact members and before the members have moved out of electrical engagement, said last mentioned means being arranged to cause pivotal movment of said lever to open said arcing contacts and interrupt the circuit in said evacuated envelope following electrical disengagemcnt of said contact members.

3. In a switch, a pair or relatively movable cooperating contact members, a pair of relatively movable arcing contacts, an evacuated envelope for housing said arcing contacts and including a flexible diaphragm whereby relative movement of said arcing contacts may be obtained by actuation of the diaphragm exterioriy of the envelope,

said evacuated envelope being supported by one of said contact members, and means including a conducting cam surface electrically connected to said other contact member for connecting said arcing contacts in shunt with said contact members following initial movement of said contact members and before the members have moved out of electrical engagement, and means cooperating with said cam surface to cause opening of said arcing contacts to interrupt the circuit in said evacuated envelope following electrical disengagement of said contact members.

i. In a switch of the type adapted to be immersed in an insulating liquid dielectric, a pair of relatively movable cooperating contact members, a pair of relatively movable arcing contacts, an evacuated. envelope for housing said arcing contacts including a flexible diaphragm whereby relative movement of said arcing contacts may be obtained by actuation of the diaphragm exterioriy of the envelope, means for normally biasing said arcing contacts to the closed position, said evacuated envelope being supported by one of said contact members, a conducting lever movable to actuate said diaphragm externally of said envelope to open said arcing contacts, said lever being electrically con nected to said one contact member through said arcing contacts, and means associated with said other contact member for engaging said lever following initial movement of said contact menu and before the members have moved out of electrical engagement to connect said arcing contacts in shunt with said contact members, said last mentioned means being arranged to move said lever to open said arcing contacts to interrupt the circuit in said evacuated envelope following electrical disengagement of said contact members, whereby said envelope encloses the arc drawn and prevents it from adversely ailect ing said liquid dielectric,

in switch, a pair of relatively movable cooperating contact members including a stationary contact and a movable blade, an insulating support on said blade, a vacuum switch mounted on said insulating support comprising a pair of normally closed interrupting contacts enclosed by an evacuated envelope having a flexible diaphragm as a wall portion thereof, an actuating member extending through said diaphragm for-operating said interrupting contacts from outside said envelope, a conductin cam surface associated with said stationary contact, a conducting member pivoted to said insulating support and electrically connected to said blade through said arcing contacts so as to complete a circuit in parallel with said contacts when said conducting member engages said cam surface, and means on said cam surface for causing movement of said conducting member to open said interrupting contacts and interrupt the current which has been transferred from said contact members to said interrupting contacts.

6. In a switch, a pair of relatively movable cooperating contact members including a stationary contact and a movable blade, an insulating support on said blade, a vacuum switch mounted on said insulating support comprising a pair of normally closed interrupting contacts enclosed by an evacuated envelope having a flexible diaphragm as a wall portion thereof, an actuating member extending through'said diaphragm for operating said interrupting contacts from outside said envelope, a conducting cam surface associated with said stationary contact,

a conducting lever pivoted to said insulating support and electrically connected to said blade through said arcing contacts so as to-complete a circuit in parallel with said contacts when said lever engages said cam surface, and means on said cam surface for causing movement of said lever to engage said actuating member thereby opening said interrupting contacts to interrupt the current which has been transferred from said contact members to said interrupting contacts.

7. In a switch, a pair of relatively movable cooperating contact members including a stationary contact and a movable blade, an insulating support on said blade, a vacuum switch mounted on said insulating support comprising a pair of normally closed interrupting contacts enclosed by an evacuated envelope having a flexible diaphragm as a wall portion thereof, an actuating member extending through said diaphragm for operating said interrupting contacts from outside said envelope, a conducting cam surface having a depressed portion electrically connected to said stationary contact, a conducting lever pivoted to said insulating support and electrically connected to said blade through said arcing contacts so as to complete a circuit in parallel with said contacts when said lever engages said cam surface prior to disengagement of said contacts said depressed portion of said cam surface causing movement of said lever to open said interrupting contacts subsequent to electrical disengagement of said contact members.

8. In a switch, a pair of relatively movable cooperating contact members including a stationary contact and a movable blade, in insulating support on said blade, a vacuum switch fixedly mounted on said insulating support comprising a pair of normally closed interrupting contacts enclosed by an evacuated envelope having a flexible diaphragm as a wall portion thereoi,.an actuating member extending through said diaphragm for operating said interrupting contacts from outside said envelope, a conducting cam surface associated with said stationary contact, a lever pivoted to said insulating support and electrically connected to said blad through said arcing contacts so as to complete a circuit in parallel with said contacts when said conducting member engages said cam surface, said lever being positioned so that when rotated it engages said actuating member to open said interrupting contacts, means normally positioning said lever out of engagement with said actuating member, and means on said cam surface for causing movement of said lever to open said interrupting contacts and interrupt the current which has been transferred from said contact members to said interrupting contacts.

ARTHUR PALME. CRIN P. McCAR'I'Y.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 532,594 Scott et a1 Jan. 15, 1895 589,582 Smith et al Sept. 7, 1897 1,783,279 Burnham Dec. 2, 1930 1,963,418 Pittman et a1 June 19, 1934 1,997,288 Anderson Apr, 9, 1935 2,121,180 Vatter June 21, 1938 2,200,122 Rawlins May 7, 1940 2,344,113 Schultz Mar. 14, 1944 FOREIGN PATENTS Number Country Date 400,716 Great Britain Nov. 2, 1933 Certificate of Correction Patent No. 2,469,203. May 3, 1949.

ARTHUR PALME ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 67, claim 2, for the Word contact read connect;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case 1n the Patent Office.

Signed and sealed this 8th day of November, A. D. 1949.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

Certificate of Correction Patent No. 2,469,203. May 3, 1949.

ARTHUR PALME ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 67, claim 2, for the word contact read connect;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 8th day of November, A. D. 1949.

THOMAS F. MURPHY,

Assistant oommiss'ioner of Patents. 

